Electric power systems generally rely on the burning of fossil fuels to meet its electrical power demands, because electrical output from steam and gas turbine generators powered by fossil fuels has been proven to be a reliable and on-demand source of energy. However, due to increasing monetary and environmental costs of the fossil fuels, there has been an increased emphasis in developing cleaner and renewable sources of power and electricity generation Examples of cleaner and renewable sources of energy include solar power, wind power, biomass power, fuel cell power, stored energy, etc. The problem with these sources is that they have not been reliable or on-demand sources for the power grid.
A conventional power distribution system generally comprises one or more renewable energy sources and one or more converters. Each individual renewable energy source is usually connected in series to form a string of renewable energy sources. In large installations, where higher input power is desired, several strings may be interconnected in parallel. The renewable energy sources are also preferably interconnected with the converters to form an overall power distribution system. Thus, when harvesting power from these renewable energy sources, each individual renewable energy source delivers to the converters an electrical voltage, which is converted into a usable form of electricity for the power grid.
Although recent technological advances have resulted in more sophisticated power distribution systems, such systems are generally not equipped to handle a device or component failure of a renewable energy source, such that the energy output is reliably provided to the power grid. For example, power distribution systems are generally designed with single-point failure modes, which may halt the entire operation of the system upon failure to a particular component of the power distribution system or renewable power source. Furthermore, the power distribution system may lack the ability to monitor the performance of the renewable power source or the power distribution system, including such performance criteria as temperature, power, current, and voltage, and the ability to maintain a minimum power output in the event of device or component failure.
Various power distribution systems have attempted to remedy the deficiencies of the currently available power distribution systems. For example, U.S. Pat. No. 8,289,742, issued to Adest et al. (“Adest I”), discloses a power distribution system comprising a plurality of renewable energy sources and a plurality of interconnected converters. The renewable energy sources are interconnected with the converters, and each individual renewable energy source delivers to the converters an electrical voltage, which is converted into a usable form of electricity. Although the power distribution system disclosed in Adest I allows the converters to share a power load with the other converters, these converters do not have ability to accommodate additional power redirected from a failed converter. The Adest I power system also lacks the ability to maintain a minimum power output in the event of component failure.
U.S. Pat. No. 8,384,243, issued to Adest et al. (“Adest II”), also discloses a power distribution system comprising a plurality of renewable energy sources and a plurality of interconnected converters. The Adest II system utilizes a temperature sensor connected to an input of a controller to adjust input power within the system. However, the system disclosed in Adest II is limited to measuring only temperature within the system and similarly lacks the ability to maintain a minimum power output in the event of component failure.
European Patent Application Number EP2533299, also filed by Adest et al. (“Adest III”), discloses a power distribution system comprising a plurality of renewable energy sources and a plurality of interconnected converters. The power distribution system disclosed in Adest III includes modules to monitor multiple parameters of each renewable energy source unit, such as current and voltage. However, like the Adest I and Adest II references, the power distribution system in Adest III does not accommodate an additional power load in the event of a converter failure.
Finally, U.S. Pat. No. 8,138,631, issued to Allen (“Allen”), discloses a power distribution system comprising a plurality of renewable energy sources that are interconnected to a plurality of converters. Allen discloses a communication bus that allows limited monitoring by a third party in the event of component failure. The Allen reference, however, does not disclose a system that can accommodate additional power loading in the event of a converter failure.
Thus, what is needed is a power distribution system that: includes a fault tolerance in the event of component failure; possesses the ability to monitor the performance of the renewable energy sources and converters; and has the ability to offset any reduced energy output resulting from a faulty device or component.